1. Field of the Invention
The present invention relates to controlling the flow of liquefied petroleum gas to a hydrocarbon gas-fueled device, and more particularly to detecting airborne hydrocarbon gas and automatically controlling the flow of hydrocarbon gas in response thereto.
2. Background of the Related Art
Combustible hydrocarbon gas is often used as a fuel source to power devices (i.e. hydrocarbon gas-fueled devices). Liquefied petroleum gas (“LPG”) refers to a category of hydrocarbon materials that are used as fuels in a gaseous form at atmospheric pressure but are stored in a pressurized, liquefied state within a pressure vessel. LPG is controllably released to atmosphere on-site to enter the gaseous state immediately prior to being consumed as a fuel in a hydrocarbon gas-fueled device. The term “LPG” may be used to refer to such a material both in its pressurized, liquefied state and its gaseous state. LPG commonly includes propane, butane, and mixtures thereof. Familiar applications for LPG include, for example, propane-burning grills, automobiles, and some domestic central heating systems.
LPG is a relatively clean-burning fuel that produces low emissions compared with the burning of other fossil fuels, such as coal. Therefore, the storage and use of LPG is generally regarded as causing minimal pollution. Hydrocarbon gas-fueled devices and vessels for storing LPG are also generally well designed and include safety mechanisms that allow for safe storage and use of LPG. However, the combustible nature of LPG can still be hazardous when not properly handled or stored. For example, a leak of LPG from a system can pose the risk of fire or explosion.